Sometimes called "mustard pumps," these dispensers deliver a measured amount of any brand laminating epoxy, The large pumps fit 1 gallon, 1/2 gallon and Raka 1 quart containers. For System3 quart and pint bottles, use the small pump. There are no 1/2 gallon System 3 bottles so if you order a three quart kit of Silvertip epoxy you will need two small pumps